import React from "react";
class DemoA extends React.Component {
    constructor(props){
        super(props);
        this.state = {
            num:1
        }
    }
    render( ){
        let {num} = this.state;
        return (
            <div>
                <h1>lei</h1>
                <h1>{num}</h1>
            </div>
        )
    }
}
export default DemoA;
